This invention concerns a feeding arrangement for samples carried in closed containers having a pierceable portion through which sample can be removed, as by a hollow needle. More specifically, this invention concerns an automatic arrangement for carrying closed sample containing tubes into an automated sample testing apparatus, removing sample from the closed tubes sequentially, supplying sample into the testing apparatus, ejecting the used tubes, and cleaning the sample removing and supplying portions between each supply step.
The just described functions are, in fact, known per se, as evidenced, for example, by apparatuses discloses in the following U.S. Pat. Nos. 3,418,080; 3,607,097; 3,768,526; 3,883,305; and 4,120,662. General problems with such prior art examples are that they are mechanically and fluidically cumbersome, expensive and not easily adaptable to the needs of many laboratories, where compactness of equipment and close proximity of human operator to instrument is desired. Because of the high cost of testing samples in hospitals and laboratories, economy and simplicity of instrumentation are now becoming the requirements, even more so than highest precision.
Some well known and accepted testing instruments heretofore have not had automatic sample feeding capabilities for reasons including the just named prior art deficiencies. One such instrument is the Coulter Counter.RTM. Model S multiparameter blood analyzer. (Coulter Counter is the Registered Trademark No. 679,591 of Coulter Electronics, Inc., Hialeah, Florida.) The system operations of such analyzer are disclosed in U.S. Pat. No. 3,549,994. If such an analyzer could receive sample tubes directly from the phlebotomist without any prediluting, or transferring to another vessel, or even opening of the tube, an act which could expose the operator and laboratory to disease, such as hepatitis, and then aspirate an aliquot of the sample from the closed tube for activating normal analyzer testing, all in a compact and inexpensive manner, then a technologic advance would be achieved.